uploadLog method Null safety

Implementation

Future<void> uploadLog() async {
  print("uploadLog");
  if (ApiService().userState.currentUser == null) return;
  print("uploadLog user is not null");

  _logQueue.add(() => _uploadTask());
  print("logQ added : ${_logQueue.length}");
  print("isScheduled: $_isScheduled");
  if (!_isScheduled) {
    _isScheduled = true;
    Timer(Duration(seconds: 0), _execute);
  }
}